What should I expect meeting my spanish boyfriend's family?

Latino families are very comfortable with each other, so take it easy and just relax. Be nice and if you don't understand something, ask. Introduce yourself and expect a hug/ kiss. As for dress, wear something appropriate like a nice dress. so his mother won't think wrong of you, and also because dresses are feminine are femininity is something valued for Latinos. Phrases to learn would be " hola es un placer conocer la." which means hello it's a pleasure to meet you. Pronounce it like this : O-la ehs oon pla-s-ehh-r c-oh-no-s-ehh-r la. Other than that don't make it look like your trying too hard. Just go with the flow and be natural.